C60 one- and two-dimensional polymers, dimers, and hard fullerite: Thermal expansion, anharmonicity, and kinetics of depolymerization
1999 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, Vol. 60, no 24, 16920-16927 p.Article in journal (Refereed) Published
We report on high-resolution thermal expansion measurements of high-temperature-pressure treated C60 [one-dimensional (1D) and (2D) polymers and “hard fullerite”], as well as of C60 dimers and single crystal monomer C60 between 10 and 500 K. Polymerization drastically reduces the thermal expansivity from the values of monomeric C60 due to the stronger and less anharmonic covalent bonds between molecules. The expansivity of the “hard” material approaches that of diamond. The large and irreversible volume change upon depolymerization between 400 and 500 K makes it possible to study the kinetics of depolymerization, which is described excellently by a simple activated process, with activation energies of 1.9±0.1 eV (1D and 2D polymers) and 1.75±0.05 eV (dimer). Although the activation energies are very similar for the different polymers, the depolymerization rates differ by up to four orders of magnitude at a given temperature, being fastest for the dimers. Preliminary kinetic data of C70 polymers are presented as well.
Place, publisher, year, edition, pages
American Physical Society , 1999. Vol. 60, no 24, 16920-16927 p.
Fullerenes, C60, C70, fullerene polymers, high pressure synthesis, thermal depolymerization, thermal expansion, activation energy, dimers, linear polymer chains, two-dimensional polymers, hard fullerite, orthorhombic polymer, tetragonal polymer, diamond
Condensed Matter Physics
Research subject Physics
IdentifiersURN: urn:nbn:se:umu:diva-23161DOI: 10.1103/PhysRevB.60.16920OAI: oai:DiVA.org:umu-23161DiVA: diva2:220665